<span>B. sam forgot to multiply.
The correct answer is
</span> x^2*y=(7^<span>2)*(9)=49*9=441 </span>
Answer:
Step-by-step explanation:
This is a Combination (as in permutation vs combination) question the symbol (n r) refers to "n choose r". This is sometimes written as nCr
i.e the question is asking you to find how many combinations each will yield when you chose r items from n item without repetition and order does not matter.
I will only do the first question for you and you can just follow the same steps to solve the rest of the questions.
Recall that

Consider question a) we are given (5 1) or ₅C₁
we can see that n = 5 and r = 1
If we substitute this into the formula:
₅C₁ = (5!) / [ (1!)(5- 1)!]
= (5!) / [ (5- 1)!]
= (5!) / (4!)
= (5·4·3·2·1) / (4·3·2·1)
= 5
hence ₅C₁ = 5
Hello!
Since we want to find out how many rooms will be needed for 44 people, we must use division.
44 ÷ 5 = 8.8
Check by multiplying:
5 × 8 = 40
Because 40 is less than the amount of people (44), we'll need to multiply by the next number in line (9):
5 × 9 = 45 (1 extra person, no biggie!)
The tour group will need 9 rooms.